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Indexed by:Journal Papers

Date of Publication:2020-12-29

Journal:FLUID DYNAMICS RESEARCH

Volume:52

Issue:4

ISSN No.:0169-5983

Key Words:secondary cylinder; flow characteristics; gap flow; deflection mechanism; vortex-shedding pattern

Abstract:Viscous flow around two unequal cylinders is simulated by solving the non-dimensional Navier-Stokes equations. A total of 13 two-dimensional numerical cases are carried out in this study for the flow fields around two adjacent cylinders atRe= 200. The ratio ofd/Dis equal to 0.25 (dandDare the diameters of the secondary and primary cylinders, respectively), the distance between two cylinders is kept as a constant (G=D), and the angle between them ranges from= 0 degrees to= 180 degrees. Firstly, six types of wake patterns are proposed and detailedly analyzed for the first time in this study. It is observed that the vortex shedding pattern is dependent on the position of the secondary cylinder. Secondly, this paper systematically analyzes the gap flow features between two cylinders for various angles, including the gap-flow strength, the deflection direction and the deflection mechanism. Additionally, this study also discusses in detail the variation characteristics of the drag coefficient, the lift coefficient, the Strouhal number and the time-averaged pressure. It is found that the drag and lift coefficients share a similar variation regularity, while the Strouhal number presents an opposite tendency with the change of the angle.